Nvidia and Advanced Micro Devices are the latest firms caught in the escalating trade war between the U.S. and China. Nvidia disclosed in an SEC filing Tuesday evening that future sales of its H20 AI accelerators to China would require a license from the U.

Nvidia ( NVDA -9.16%) shares fell more than 7% on Wednesday morning, after the company disclosed new export restrictions on its artificial intelligence (AI) chips. Specifically, the company must now obtain licenses from the U.S. government to sell its H20 processors in China.

Nvidia Corp.’s shares were tumbling in after-hours trading Tuesday, after the chip giant disclosed in a regulatory filing that it expects to include charges of up to $5.5 billion in its fiscal first quarter related to licensing of its chips to the Chinese market.